AIMS: Electromechanical coupling in patients receiving cardiac resynchronization therapy (CRT) is not fully understood. Our aim was to determine the best combination of electrical and mechanical substrates associated with effective CRT. METHODS AND RESULTS: Sixty-two patients were prospectively enrolled from two centres. Patients underwent 12-lead electrocardiogram (ECG), cardiovascular magnetic resonance (CMR), echocardiography, and anatomo-electromechanical mapping (AEMM). Remodelling was measured as the end-systolic volume (ΔESV) decrease at 6 months. CRT was defined effective with ΔESV ≤ -15%. QRS duration (QRSd) was measured from ECG. Area strain was obtained from AEMM and used to derive systolic stretch index (SSI) and total left-ventricular mechanical time. Total left-ventricular activation time (TLVAT) and transeptal time (TST) were derived from AEMM and ECG. Scar was measured from CMR. Significant correlations were observed between ΔESV and TST [rho = 0.42; responder: 50 (20-58) vs. non-responder: 33 (8-44) ms], TLVAT [-0.68; 81 (73-97) vs. 112 (96-127) ms], scar [-0.27; 0.0 (0.0-1.2) vs. 8.7 (0.0-19.1)%], and SSI [0.41; 10.7 (7.1-16.8) vs. 4.2 (2.9-5.5)], but not QRSd [-0.13; 155 (140-176) vs. 167 (155-177) ms]. TLVAT and SSI were highly accurate in identifying CRT response [area under the curve (AUC) > 0.80], followed by scar (AUC > 0.70). Total left-ventricular activation time (odds ratio = 0.91), scar (0.94), and SSI (1.29) were independent factors associated with effective CRT. Subjects with SSI >7.9% and TLVAT <91 ms all responded to CRT with a median ΔESV ≈ -50%, while low SSI and prolonged TLVAT were more common in non-responders (ΔESV ≈ -5%). CONCLUSION: Electromechanical measurements are better associated with CRT response than conventional ECG variables. The absence of scar combined with high SSI and low TLVAT ensures effectiveness of CRT.

• Klíčová slova
• Activation time, Cardiac resynchronization therapy, Electromechanics, Interventricular delay, Intraventricular conduction, Left-bundle branch block,
• MeSH
• blokáda Tawarova raménka MeSH
• echokardiografie MeSH
• elektrokardiografie metody   MeSH
• funkce levé komory srdeční fyziologie   MeSH
• jizva MeSH
• lidé MeSH
• srdeční resynchronizační terapie * škodlivé účinky   metody   MeSH
• srdeční selhání * diagnóza   terapie   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Cardiac resynchronization therapy is a valuable tool to restore left ventricular function in patients experiencing dyssynchronous ventricular activation. However, the non-responder rate is still as high as 40%. Recent studies suggest that left ventricular torsion or specifically the lack thereof might be a good predictor for the response of cardiac resynchronization therapy. Since left ventricular torsion is governed by the muscle fiber orientation and the heterogeneous electromechanical activation of the myocardium, understanding the relation between these components and the ability to measure them is vital. To analyze if locally altered electromechanical activation in heart failure patients affects left ventricular torsion, we conducted a simulation study on 27 personalized left ventricular models. Electroanatomical maps and late gadolinium enhanced magnetic resonance imaging data informed our in-silico model cohort. The angle of rotation was evaluated in every material point of the model and averaged values were used to classify the rotation as clockwise or counterclockwise in each segment and sector of the left ventricle. 88% of the patient models (n = 24) were classified as a wringing rotation and 12% (n = 3) as a rigid-body-type rotation. Comparison to classification based on in vivo rotational NOGA XP maps showed no correlation. Thus, isolated changes of the electromechanical activation sequence in the left ventricle are not sufficient to reproduce the rotation pattern changes observed in vivo and suggest that further patho-mechanisms are involved.

• Klíčová slova
• Lagrangian particle tracking, NOGA XP, cardiac mechanics, electromechanical mapping, finite element simulation, torsion, wringing,
• Publikační typ
• časopisecké články MeSH